The AVL 8-Mode test is a steady-state engine test procedure designed to closely correlate with the exhaust emission results over the US FTP transient cycle for heavy-duty engines, especially in regards to NOx emissions. The test includes 8 steady-state modes. The composite value is calculated by applying weighing factors on the modal results.

The sequential engine operating points are as follows:

Table 1
AVL 8-Mode Heavy-Duty Cycle
Mode% Engine Speed*% LoadWeight factor†
10035.00
211256.34
321632.91
432843.34
5100188.40
6954010.45
7956910.21
889957.34
* Normalized speed: 0% = low idle, 100% = rated speed
† Relative weight factors, not normalized (they do not add to 100%)

The relative weights of particular modes are represented by the area of bubbles in Figure 1.

AVL 8-Mode

Figure 1. AVL 8-Mode Heavy-Duty Cycle